In recent years, organic EL displays that employ an organic EL system in which carriers are injected into an organic solid from an electrode to emit light from a flat surface have actively been developed as light-emitting type displays. The organic EL displays can be divided into passive matrix type and active matrix type, for example, depending on how the displays are driven. The former type display allows pixels arranged in a matrix to emit light by line-at-a-time driving method. The latter type has a switching element for each of pixels arranged in a matrix and the switching elements are controlled to drive the pixels so that they emit light individually.
According to the driving method by the active matrix type organic EL display, the switching circuits control light emission of the pixels on a pixel basis, and therefore the display has attracted attention particularly as an optimum display for moving picture. There are bottom emission type displays that extract emitted light toward the glass substrate and the top emission type displays that extract emitted light to the opposite side to the glass substrate.
A bottom emission type, active matrix organic EL panel is provided with a switching circuit on a pixel basis, and light is emitted toward the glass substrate. Therefore, the part of the switching circuits that occupies half the area of the pixel inevitably becomes a non-light emitting region. In addition, three light emitting regions for three colors R (red), G (green), and B (blue) that are necessary for full color display are produced by coloring the organic EL light emitting layer discretely corresponding to the colors. Therefore, a registration margin (dm) for discrete coloring between adjacent light emitting regions in different colors is necessary, and this dm portion constitutes a non-light emitting region.
In a conventional display, the three light emitting regions for R, G, and B and the switching circuit portions are arranged continuously based on the colors (see FIG. 4 for the arrangement in the horizontal (X-) direction). As the registration margin (dm) depends on the registration precision by the pixel film deposition device and the processing precision of the pattering mask, how much the registration margin (dm) can be reduced is limited, and the minimum value for the margin dm is generally 20 μm (corresponding to ±10 μm). In this case, the width of each light emitting region is smaller as the resolution increases. However, the minimum value for dm is fixed, and therefore the ratio of dm occupied in the pixel increases, which lowers the ratio of the light emitting regions (aperture ratio) if higher resolution is to be achieved. With a smaller aperture ratio, the luminance is lowered, and therefore the amount of current that contributes to the light emission should be increased to keep the luminance in a necessary level. This gives rise to increase in power consumption.
The present invention was devised in view of the above described problems, and it is an object of the present invention to provide a display device having a bottom emission type, active matrix organic EL panel that efficiently secures a sufficient aperture ratio, has pixel arrangement in which the aperture ratio is hardly a trade off for higher resolution, and can operate with reduced power consumption for obtaining necessary luminance and contribute to downsizing of the driving circuit and the device as a whole, and a manufacturing method that allows the configuration of such a display device to be readily provided with reliability.